Defect-Free Surface Waves

Abstract

Interfaces between physical media can support a special type of localized mode known as surface waves. In solids, electronic surface waves generated in crystals at the edge of truncated periodic potential are commonly explained as the manifestation of either Tamm or Shockley localization mechanisms. Optical analogs of Tamm and Shockley states have also been studied extensively in different types of periodic photonic structures, where such optical surface waves are particularly attractive for optical sensing, measurement and characterization applications. Usually, a surface defect is required for surface waves to exist in straight photonic lattices composed of identical waveguides. Discrete optical surface solitons have been recently observed in nonlinear arrays, where such a defect is induced due to nonlinearity.